Fecal endocrine profiles and ejaculate traits in black-footed cats ( Felis nigripes) and sand cats ( Felis margarita)

Abstract

Information regarding the reproductive biology of black-footed cats (BFC) and sand cats (SC) is extremely limited. Our objectives were to: (1) validate fecal hormone analysis (estrogens, E; progestagens, P; androgens, T) for noninvasive monitoring of gonadal activity; (2) characterize estrous cyclicity, ovulatory mechanisms, gestation, and seasonality; and (3) evaluate male reproductive activity via fecal androgen metabolites and ejaculate traits. In both species, the estrous cycle averaged 11–12 days. In BFC ( n = 8), estrus lasted 2.2 ± 0.2 days with peak concentrations of E (2962.8 ± 166.3 ng/g feces) increasing 2.7-fold above basal concentrations. In SC ( n = 6), peak concentrations of E (1669.9 ± 83.5 ng/g feces) during estrus (2.9 ± 0.2 days) were 4.0-fold higher than basal concentrations. Nonpregnant luteal phases occurred in 26.5% (26 of 98) of BFC estrous cycles, but were not observed in SC (0 of 109 cycles). In both species, P concentrations during pregnancy were elevated (32.3 ± 3.0 μg/g feces BFC; 8.5 ± 0.7 μg/g feces SC) ∼10-fold above basal concentrations. Fecal T concentrations in males averaged 3.1 ± 0.1 μg/g feces in BFC and 2.3 ± 0.0 μg/g feces in SC. Following electroejaculation, 200 to 250 μl of semen was collected containing 29.9 (BFC) to 36.5 (SC) × 10 6 spermatozoa with 40.4 (SC) to 46.8 (BFC)% normal morphology. All females exhibited estrous cycles during the study and spermatozoa were recovered from all males on every collection attempt, suggesting poor reproductive success in these species may not be due to physiological infertility.